Cleaning compositions for decontaminating and cleaning skin, eyes, teeth and hair generally contain various surfactants for the purpose of cleaning and decontamination. In order to further improve foaming and cleaning effects of a cleaning composition, more than one surfactant is often added. A certain amount of a solvent, especially water or a mixed solvent of water and polyols, is also often used in a cleaning composition to dissolve surfactants and active ingredients, thus allowing easier use of the product. Although it is not essential to selectively add beautifying and cleaning adjuvants, more than one beautifying and cleaning adjuvants are also added so as to achieve the usability of a cleaning composition in the field of personal care products.
Cleaning and decontamination alone are not enough for a cleaning composition, and consumers wish to buy a cleaning composition with thick appearance. Consumers think that a thick cleaning composition is a product with fine performance and higher active matter content, and therefore believe that it is safe and cost-effective. Meanwhile, a thick cleaning composition can be packaged in a hose or a similar packaging container such that the cleaning composition will not flow out like water when the hose cap is opened. A thick cleaning composition is beneficial to reducing packaging cost for manufacturers, while convenient to use and carry for consumers.
Most of the traditional thick cleaning compositions currently available on the market are those compositions with high-content fatty acid soap as a major component, such as “a stable foaming cream” with fatty acid soap as a major component described in EP1166747 filed by Oreal. But thick cleaning compositions with fatty acid soap as a major component have a higher pH value (usually the pH value is 9-11), which will cause skin allergy, redness and swelling, and hair damage to some consumers. From the perspective of safety, cleaning compositions with fatty acid soap as a major component have no substantial progress over bar soap with regard to use safety of consumers.
In the art, to produce a thick cleaning composition with a pH value in a neutral or weakly acidic range, various associating thickening components are commonly used in its formula to achieve the purpose of product thickening. Associating thickening components are mainly associating polymers, which are usually polymers with hydrophilic groups and hydrophobic groups formed by grafting a small number of hydrophobic groups such as alkyl chains and alkyl oxyethyl chains to water-soluble polymers. Hydrophobic groups in surfactants and hydrophobic groups in associating polymers associate with each other in the presence of the surfactants due to mutual association of the hydrophobic groups, and then the surfactants form micelles (like strings of small water droplets on a cobweb) on or near chains of the associating polymers, thus increasing the viscosity of the cleaning composition due to this association. Such associating polymers, such as a hydrophilic amphoteric polymer described in WO00/39176 filed by Bfgoodrich Co., are used as components in personal care products to achieve the purpose of thickening and rheology modification.
Cleaning compositions using associating polymer components have very obvious disadvantages as follows: thick cleaning compositions will often be adhered to skin and hair surfaces during use such that they are difficult to be spread out, and the cleaning compositions will have large viscosity change due to the influence of temperature change, thus they look like fruit jelly in winter but are as thin as water in summer. In particular, the cleaning compositions are not easy to be spread out when used in winter, thus affecting foaming speed and foaming effect thereof. For cleaning compositions, foaming speed and foaming effect belong to another important factor for consumers to evaluate product quality. Accordingly, consumers are not satisfied with and can not accept the cleaning compositions using associating thickening components.